To provide an exhaust turbine type supercharger for an internal combustion engine capable of reducing oil leakage.
A turbine impeller 12 rotationally driven by exhaust gas of an internal combustion engine is fixed at a turbine shaft 10. The turbine shaft 10 is supported in a radial direction by a radial bearing 20 and mounted on a bearing housing 30. The turbine shaft 10 is formed between the turbine impeller 12 and the radial bearing part 20, and a stepped part 14 is provided such that the turbine side is further increased in an outside diameter than the radial bearing part side. The bearing housing 30 has an oil drain 34 to drain oil lubricating the radial bearing part 20. A distance L from the side wall surface of the radial bearing to the stepped part is set to a distance, at which oil moved from the end part of a radial bearing is brought into a state to be non-contact with the stepped part, at a region where the number Nt of revolutions of a turbine is higher than the number Nti of revolutions of a turbine during idle operation of an engine.
KATSUNO TOSHIYUKI
SENDA TERUO
HITACHI CAR ENG CO LTD
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